Circuit Documentation

Summary

This circuit is designed to control a robot with obstacle avoidance and line-following capabilities. It uses an Arduino UNO as the central microcontroller to manage inputs from an HC-SR04 ultrasonic sensor and two IR sensors, and to control a servo and two DC motors through an L298N motor driver. A 9V battery powers the circuit, and a rocker switch is used to turn the power supply on and off.

Component List

HC-SR04 Ultrasonic Sensor

• Description: This sensor measures distance by emitting ultrasonic waves and measuring the time it takes for the echo to return.
• Pins: VCC, TRIG, ECHO, GND

Arduino UNO

• Description: A microcontroller board based on the ATmega328P, used for controlling the various components in the circuit.
• Pins: UNUSED, IOREF, Reset, 3.3V, 5V, GND, Vin, A0-A5, SCL, SDA, AREF, D0-D13

IR Sensor

• Description: An infrared sensor used for line detection.
• Pins: out, gnd, vcc

L298N DC Motor Driver

• Description: A motor driver module that controls the direction and speed of two DC motors.
• Pins: OUT1-OUT4, 12V, GND, 5V, 5V-ENA-JMP-I/O, +5V-J1/J2, ENA/ENB, IN1-IN4

Rocker Switch

• Description: A switch used to connect or disconnect the power supply to the circuit.
• Pins: output, input

Hobby Gearmotor with 48:1 Gearbox

• Description: A DC motor with a gearbox used to drive the robot's wheels.
• Pins: pin 1, pin 2

9V Battery

• Description: The power source for the circuit.
• Pins: -, +

Servo

• Description: A motor capable of precise control of angular position, used for steering or other actuation.
• Pins: gnd, vcc, pulse

Wiring Details

HC-SR04 Ultrasonic Sensor

• VCC connected to 5V power supply
• TRIG connected to Arduino UNO pin D8
• ECHO connected to Arduino UNO pin D9
• GND connected to common ground

Arduino UNO

• 5V and GND pins provide power and ground to other components
• Digital pins D8 and D9 connected to HC-SR04 Ultrasonic Sensor
• Digital pins D12, D13, D10, D11 control the L298N motor driver
• Digital pins D6 and D5 control the speed of the motors via the L298N motor driver
• Digital pins D4 and D2 connected to IR sensors
• Digital pin D1 connected to Servo pulse pin

IR Sensors

• out pin of one sensor connected to Arduino UNO pin D4
• out pin of the other sensor connected to Arduino UNO pin D2
• vcc pins connected to 5V power supply
• gnd pins connected to common ground

L298N DC Motor Driver

• IN1-IN4 connected to Arduino UNO pins D12, D13, D10, D11 for motor control
• ENA and ENB connected to Arduino UNO pins D5 and D6 for speed control
• OUT1-OUT4 connected to the pins of two Hobby Gearmotors
• 12V connected to the output of the rocker switch for power
• 5V and GND connected to 5V power supply and common ground, respectively

Rocker Switch

• input pin connected to the + pin of the 9V Battery
• output pin connected to the 12V pin of the L298N motor driver

Hobby Gearmotors

• pin 1 of one motor connected to OUT1 of the L298N motor driver
• pin 2 of the same motor connected to OUT2 of the L298N motor driver
• pin 1 of the other motor connected to OUT4 of the L298N motor driver
• pin 2 of the other motor connected to OUT3 of the L298N motor driver

9V Battery

• • pin connected to the input of the rocker switch
• • pin connected to common ground

Servo

• gnd pin connected to common ground
• vcc pin connected to 5V power supply
• pulse pin connected to Arduino UNO pin D1

Documented Code

// Definición pines EnA y EnB para el control de la velocidad
int VelocidadMotor1 = 6; 
int VelocidadMotor2 = 5;

// Definición de los pines de control de giro de los motores In1, In2, In3 e In4
int Motor1A = 13; 
int Motor1B = 12;  
int Motor2C = 11; 
int Motor2D = 10; 

// Sensores infrarrojo - izquierdo y derecho
int infraPin  = 2;    
int infraPin1 = 4;

// Variables para la captura de los valores: 0 - fondo claro y 1 - línea negra
int valorInfra = 0;  
int valorInfra1 = 0;  

// Ultrasonicos
#define PIN_TRIG 9
#define PIN_ECHO 8
 
long duration, distancia;
// Configuración inicial
void setup() {
  Serial.begin(9600);
  
  delay(1000);
  //configuración del ultrasonico
  pinMode(PIN_TRIG, OUTPUT);
  pinMode(PIN_ECHO, INPUT);
  // Establecemos modo de los pines de los sensores infrarrojo
  pinMode(infraPin, INPUT);    
  pinMode(infraPin1, INPUT);

  // Establecemos modo de los pines del control de motores
  pinMode(Motor1A,OUTPUT);
  pinMode(Motor1B,OUTPUT);
  pinMode(Motor2C,OUTPUT);
  pinMode(Motor2D,OUTPUT);
  pinMode(VelocidadMotor1, OUTPUT);
  pinMode(VelocidadMotor2, OUTPUT);

  // Configuramos los dos motores a velocidad 150/255
  analogWrite(VelocidadMotor1, 150); 
  analogWrite(VelocidadMotor2, 180);  

  // Configuramos sentido de giro
  digitalWrite(Motor1A, LOW);
  digitalWrite(Motor1B, LOW);
  digitalWrite(Motor2C, LOW);
  digitalWrite(Motor2D, LOW);
}

// Ejecución contínua
void loop() {
  // Ultrasonico: Primero, generar un pulso corto de 2-5 microsegundos.
  digitalWrite(PIN_TRIG, LOW);
  delayMicroseconds(5);
  digitalWrite(PIN_TRIG, HIGH);
  // Después de ajustar un nivel de señal alto, esperamos unos 10 microsegundos. En este punto el sensor enviará señales con una frecuencia de 40 kHz.
  delayMicroseconds(10);
  digitalWrite(PIN_TRIG, LOW);
  // Tiempo de retardo de la señal acústica en el sonar.
  duration = pulseIn(PIN_ECHO, HIGH);
  // Ahora es el momento de convertir el tiempo a distancia
  distancia = (duration / 2) / 29.1;
  Serial.print("Distancia al objeto: ");
  Serial.print(distancia);
  Serial.println(" см.");
  
  // Leemos el valor de los infrarrojo: 0 - fondo claro y 1 - línea negra
  valorInfra = digitalRead(infraPin);   
  valorInfra1 = digitalRead(infraPin1);

  Serial.println(valorInfra);
  Serial.println(valorInfra1);
  if (distancia > 10){ //mientras no detecte nada a cierta distancia no se detiene   
      // Cuatro escenarios: De frente      
      if(valorInfra == 0 && valorInfra1 == 0){
        Serial.println("Ninguno en linea");
        
        // Modificamos sentido de giro de los motores
        digitalWrite(Motor1A, HIGH);
        digitalWrite(Motor2D, HIGH);
        delay(20);                      
        digitalWrite(Motor1A, LOW);
        digitalWrite(Motor2D,LOW);
        delay(20);                     
      }
    
      // El robot encuentra línea negra con el infrarrojo derecho y hay que corregir girando a la derecha
      if(valorInfra == 0 && valorInfra1 == 1){  
        Serial.println("Derecho en linea");
        
        // Modificamos sentido de giro de los motores
        digitalWrite(Motor1A, LOW);
        digitalWrite(Motor2D,LOW);
        delay(25);
        digitalWrite(Motor1A, HIGH);
        digitalWrite(Motor2D,LOW);
        delay(20);
      }
    
      // El robot encuentra línea negra con el infrarrojo izquierdo y hay que corregir girando a la izquierda
      if(valorInfra ==